Multiple items within a list item

I want my end users to be able to enter a list like this

<ol>
   <li>
      <h3>Title 1</h3>
      <p>Description of item 1</p>
   </li>
   <li>
      <h3>Title 2</h3>
      <p>Description of item 2</p>
   </li>
</ol>

But when I test using the numbered list toolbar button it numbers every item. Is there a way that I can instruct my users to do this?

Thanks!
Jon